1. Field of the Invention
This invention pertains generally to circuit interrupters and, more particularly, to direct current or battery disconnect apparatus.
2. Background Information
Known technology provides minimal protection for the electrical power circuit of a vehicle. For example, some vehicles, such as trucks or cars, use fuses. Recently, some automotive vehicles employ fuses and a relay disconnect that opens in the event of a crash.
Direct current (DC) disconnecting switches are known to provide a rapid mechanism to disconnect batteries or other DC power supplies in the event of serious electrical faults. For example, battery disconnect devices (BDDs) help protect and provide disconnection for both 14 VDC and 42 VDC systems. For example, a Delphi® BDD helps provide post-collision circuit protection for electrical cables connected to the battery. A base-level BDD is a low-cost, battery cable circuit protection device that responds during a significant collision. The device is actuated by a signal from the air bag controller or other crash sensors. Some BDDs enable the vehicle to remain operational, including the ability to restart without manual intervention, if the collision does not cause a battery cable circuit fault. Replacement of the BDD unit is necessary following actuation to provide proper operation in future conditions. An up-level version of the BDD is purported to provide more sophisticated functions and additional features.
A First Technology™ battery cut off switch (BCO) is employed by motor vehicles that require the electrical system (e.g., without limitation, 12 VDC; 24 VDC; 42 VDC) to be disconnected in a collision. Following a crash situation, the BCO typically responds from a remote signal in 3 mS, disabling the electrical system. Certain circuits (e.g., door locks, windows, hazard lights) identified by the user, however, will retain battery power. The BCO provides manual/electric disconnect and/or reset, short circuit protection, voltage/current monitoring, a visual status indicator and a battery saver.
An automatic heavy duty computerized on/off PriorityStart!® switching system protects battery voltage and starting power. If the battery voltage drains below 11.7 VDC when the engine is off, then it automatically disconnects the load, which permits the battery voltage to recover.
A known battery disconnect relay uses a latching relay, which is capable of carrying relatively heavy currents and requires no power to stay open or closed.
It is known to provide a remotely controlled battery disconnect that uses a remote control channel (e.g., a momentary switch) to shut off a battery from outside a car. The momentary switch is pushed once to connect the battery, and is pushed again to disconnect the battery feed.
It is also known to provide a dual battery system in which one battery is used for starting an engine while the other battery is used to power auxiliary loads. A battery selector switch enables the use of the first battery, the second battery or both batteries simultaneously.
It is further known to provide an AC induction motor controller designed for 24 to 80 VDC battery systems for a wide range of battery-powered vehicles. The motor controller includes battery monitoring, I/O control and CANbus communications.
Japanese Patent Application No. 11-136846 discloses an abnormal current shut-off device for an automobile wiring system wherein the current flowing through the wiring system is shut off independently of a fuse as a result of intermittent shorts in the wiring system which make it difficult for a fuse to melt. Current flowing through the wiring system connecting a DC power source and an electrical load is sensed by a current sensor, which generates a sensed output. When the sensed output is an abnormal level corresponding to a sudden major abnormal current, a dead short determining circuit determines it to be abnormal. When the sensed output is an abnormal level corresponding to an intermittent low abnormal current, a layer short determining circuit determines it to be abnormal. A MOSFET shuts off the flow of current to the wiring system based on either of these two determinations.
There is room for improvement in direct current or battery disconnect apparatus.